....Although, it seems Australian accents are kept for Mandalorians....

BZZT ! Gosh, you obviously cannot pick a New Zealand Maori accent ! Both Fetts have them (Temeura Morrison and Daniel Logan)

Though there are some aussie actors in AOTC/ROTS. ie. all the Larses are aussie actors, none of them kept their accent.

I'd say an outer rim accent is closer to an american one eg. Luke, Biggs.
Inner rim would be more typical Coruscanti. ie British sounding. eg. Admiral Ozzel, General Veers, Capt Piett. Capt Needa etc. Of course alot of this had to do with the fact that those scenes in ESB/ANH/ROTJ were shot in England... lolz